1. Field of the Invention
This invention relates in general to certain new and useful improvements in a mixer or shredder apparatus of the type used for mixing and shredding of bulk material, such as farm feed material, and more particularly, to a mixing and shredding apparatus in which power to a shredding or mixing member can be reduced or increased by manual intervention without power interruption.
2. Brief Description of the Related Art
There have been several proposed and several commercially available mixers and shredders for mixing of bulk material or shredding of bulk material which utilize a tank containing the bulk material as well as one or more augers located with that tank and which rotate for accomplishing the shredding or mixing operation. The same apparatus is adapted for both mixing or shredding depending upon the type of auger which may used in the shredding tank and/or the rate of rotation thereof. In addition, and in the prior art, there are both horizontally arranged mixers and vertically arranged mixers.
Each of these proposed and commercially available prior art mixers generally comprise a mixer housing or tank forming a vat or chamber to receive the livestock feed or other material to be mixed or shredded, along with an auger extending into the housing and operated by an external power source. In the case of the vertically arranged mixer or shredder, the auger itself is vertically disposed.
Exemplary of such prior art shredders and mixers is U.S. Pat. No. 5,462,354, dated Oct. 31, 1995, for livestock stock feed mixer. In most cases, the shredder or mixer is used in a field environment as, for example, a farm, and is usually mounted on a chassis adapted for pulling movement. Again, the aforesaid U.S. Pat. No. 5,462,354 is exemplary of this type of arrangement. In these cases, the shredder or mixer may be pulled by a conventional tractor.
Generally, all farm tractors are provided with a means for coupling a power take off shaft commonly referred to as a xe2x80x9cPTOxe2x80x9d shaft. The engine of the tractor is operatively coupled to the drive wheels of the tractor for driving the tractor and which, in turn, pulls the mixer or shredder. The PTO shaft shares the power from this tractor engine for driving an auger or other rotating shredding or mixing member in the shredder or mixer.
Because of the increased demand for animal feed, the shredding and mixing tanks have been constructed with increasing sizes. In fact, there have been numerous cases where a farm owner will attempt to literally increase the size of the tank by extending the height the mixing tank in order to mix or shred a greater amount of feed material.
The amount of power which is consumed by the auger in the shredding or mixing tank is materially affected by the amount of bulk material in the tank. Moreover, the power required is a function of the density of the feed material. In addition, moisture which may be entrained in the material will also substantially affect the power requirements for rotating the auger of that mixer or shredder at a desired speed.
Because of the fact that the power to the shredder or mixer can vary with the power drawn by the wheels of the tractor, this power can be increased or decreased substantially thereby affecting the efficiency of operation of the shredder or mixer. In fact, if the tractor is traveling in a downhill mode, because of inertial forces, little power is necessary at that point in time for driving the tractor and, hence, there could be an excess of power literally delivered to the auger thereby causing the auger to overload and stress some portion of the entire mixing or shredding system.
Because of the developments in the shredding and mixing apparatus, the power required for rotation of the auger is constantly increasing, as aforesaid, thereby creating the need for variable transmission ratios between the engine and the auger. As a result, many of these shredders and mixers are provided with a gear box or transmission to change the power ratio to the auger of the shredder or mixer.
One of the main problems with the manual transmissions which have been used is the fact that in order to increase or decrease power to the auger, the user must change the gear ratio. Thus, if the user wishes to increase the power to the auger, he or she will select a lower gear ratio. However, with the manual transmission, the power train must first be disconnected. However, when power is interrupted to the auger, even momentarily, the additional problem arises, in that the power for restarting rotation of the auger can be considerable. Thus, forces are exerted upon the drive shaft and, in effect, the entire power train to the shredding and mixing apparatus. In some cases, this application of sudden power may result in damage to the drive shaft or other portions of the power train.
Another mixer/shredder apparatus which is effectively self-propelled by its own power source is that illustrated in U.S. Pat. No. 5,782,559, dated Jul. 21, 1998, for Self-Propelled Material Mixer. In this case, the power source is also shared, that is, used for driving the apparatus and also operating the auger of the apparatus. This power sharing gives rise to the types of problems mentioned above. An auger of the type which can be used in these mixing/shredding apparatus is disclosed in U.S. Pat. No. 5,732,892, for Self-Loading Auger.
One problem which arises is the fact that when the tractor or trailer is shifted into gear for driving, the torque which is used for operating the shredder or mixer is substantially reduced. This imposes additional stresses not only on the engine of the tractor, but on the shredding or mixing apparatus itself. These problems are identified in the aforesaid U.S. Pat. No. 5,462,354.
There has been at least one attempt to use an automatic transmission for incorporation in this drive train and which is shown in U.S. Pat. No. 5,462,354, as aforesaid. The automatic transmission, however, does not really solve the problems mentioned above and, in fact, in many ways, is less efficient than a manual transmission. In the case of the automatic transmission, the problem often arises that the speed of the power train is so low that the time required to mix and cut silage or other material can become excessive. There is little that the operator of the apparatus can do to affect the transmission ratio and, hence, the cutting and mixing process.
Another significant problem which has arisen in connection with the use of the automatic transmission is the fact that the transmission may literally cycle between gears. Thus, in a lower gear, the transmission may sense the need to switch to a higher gear. However, at the higher gear, the transmission may sense a need for more power and, hence, shift to a lower gear. This cycling, particularly if it becomes a constant cycling, can severely damage the transmission or other portion of the drive train.
There have been other attempts to account for variations in the loads imposed on a mixer or shredder and for the variations in loads on a power source therefor. One such attempt, for example, includes European Patent Application No. EP 0 880 890 A1, dated May 19, 1998, and which discloses a mixer in which the required drive power of the mixing or shredding member can be temporarily reduced during the initial stages of the mixing process and, particularly, when large chunks of material are present. Also, in European Patent Application No. EP 0 880 890 A1, dated May 19, 1998, a mixer or shredder is provided with a vertically arranged auger and which uses a reversible speed reduction gear arrangement to enable alteration of the speed of the motion of the mixing unit. In effect, a transmission arrangement is provided enabling selection of two different transmission ratios. Drive power can optionally be used for other purposes during this mixing process.
In U.S. Pat. No. 4,384,455, dated May 24, 1983, for hydraulic motor bypass apparatus, a fluid bypass system with a bypass valve automatically operates to stop motion of a feed table when operation of the apparatus stalls through excessive load. In European Patent Application No. 0 659 470 A1, dated Dec. 27, 1993, a mixer or shredder is disclosed using a frustro-conical container with a generally vertically arranged auger for shredding and mixing. This device uses a transmission employing a reduction unit on the bottom of the container or a transmitting motion from a driving motor to the auger. In this particular shredder and mixer, the transmission is mounted in such manner that the auger can be located in a cantilevered fashion without any upper supporting cross member.
French Patent No. 2,737,386, dated Feb. 7, 1997, also discloses a hydraulic system utilizing valves which will function as a transmission.
In European Patent Application No. 0 659 470 A1, dated Dec. 27, 1993, there is provided an independently powered vertically arranged auger located within a frustro-conical container and which is mounted on a tractor and operated with a common power source. However, in this case, a double variable delivery hydraulic pump is coupled both to the drive unit and to the auger for both driving the truck and powering the auger. However, a complex hydraulic system is necessarily employed in the construction thereof.
There have been several proposals for dealing with the problem of changing the power available to an auger in response to the density of the bulk material and the amount of the bulk material, in addition to the automatic transmission proposal set forth in U.S. Pat. No. 5,462,354. In European Patent Application No. 0 659 470 A1, dated Dec. 27, 1993, there is provided an independently powered vertically arranged auger located within a frustro-conical container and which is mounted on a tractor and operated with a common power source. However, in this case, a double variable delivery hydraulic pump is coupled both to the drive unit and to the auger for both driving the truck and powering the auger. However, a complex hydraulic system is necessarily employed in the construction thereof.
It would be desirable to provide a shredding and/or mixing apparatus which can be powered through a PTO shaft from a tractor or other vehicle, or otherwise being powered by a dedicated power source, but which has the capability of causing a shifting of the gear ratio between the auger and power source without any interruption of power to the auger.
It is, therefore, one of the primary objects of the present invention to provide a shredding and mixing apparatus having a tank for bulk material and an auger for shredding or mixing the bulk material and which is powered from a power source with a manually actuable power shift transmission enabling the power ratio to be altered without interruption of power.
It is another object of the present invention to provide a shredding or mixing apparatus of the type stated which utilizes a transmission in which the transmission ratio between the power plant operating the shredding or mixing apparatus and the shredding or mixing member of that apparatus can be manually reduced or increased without any interruption of power to the shredding or mixing member.
It is a further object of the present invention to provide a shredding or mixing apparatus of the type stated in which an increase or decrease in forces acting on the power plant used for powering the auger can be compensated by reduction or increase of the transmission ratio between the power plant and the shredding or mixing member.
It is also an object of the present invention to provide a shredding or mixing apparatus of the type stated which utilizes a manually operable power shift transmission and which provides for manual shifting of the power ratio between a dedicated power source or a power source derived from a PTO shaft and a mixing or shredding apparatus without otherwise interrupting the power from the power source itself.
It is another salient object of the present invention to provide a transmission for delivery of power from a power source to a mixer or shredder in which the power delivered from that power source can vary depending on other loads imposed on the power source and which does not materially interfere with the shredding or mixing operation with power shifting compensation.
It is still a further object of the present invention to provide a transmission which can be used for shredding and mixing apparatus of the type stated and which allows for manual selection of a desired gear ratio and manual intervention to change that gear ratio without interruption of the power to the shredding or mixing apparatus.
It is yet another salient object of the present invention to provide a shredding or mixing apparatus of the type stated utilizing the manually actuable power transmission of the invention and which can be constructed at a relatively low unit cost and which is highly efficient in operation.
It is still a further object of the present invention to provide a manually actuable power transmission of the type stated which can be constructed with relatively inexpensive modification of an existing automatic transmission.
It is still another object of the present invention to provide a method of changing the transmission ratio between a power plant and shredding or mixing member without interruption of power to the shredding or mixing member.
With the above and other objects in view, our invention resides in the novel features of form, construction, arrangement and combination of parts and components presently described and pointed out in the claims.
The present invention relates in general terms to a material shredder or mixer which is carried on a transportable mobile chassis and incorporates a mixing tank and vertically arranged auger disposed within that mixing tank. It should be understood in connection with the present invention that both mixing and shredding are essentially accomplished by the same apparatus and, even to some extent, the same auger used with that apparatus. Substitution of one type of auger for another could be made, if desired. Thus, it should also be understood in connection with the present invention that the term xe2x80x9cmixing apparatusxe2x80x9d or xe2x80x9cmixerxe2x80x9d will also encompass shredding apparatus and shredders and vice a versa.
The shredder or mixer may be provided with its own dedicated power source, or otherwise, power may be derived from a power take off shaft on a driving tractor or truck for operation of an auger in the apparatus. In either case, a transmission is provided and preferably located at the power source for changing the transmission ratio between the power source and a shredding or mixing member without any interruption of power to the auger in the mixing or shredding apparatus.
More specifically, the present invention is achieved by using a transmission in which the transmission ratio between the power plant and the shredding or mixing member can be reduced or increased without interruption of power, such that increased demand acting on the power plant, resulting in reduced power to the auger, is compensated for by a reduction in the transmission ratio between the power plant and the shredding to mixing member. This enables the shredding or mixing apparatus to be mounted on a stationary rotating power plant while the container of this apparatus is being filled or is completely filled.
In accordance with the invention, the power plant which is used is generally a hydrocarbon combustion engine power plant, such as a gasoline engine or a diesel engine. Further, the engine can be driven by any of a variety of fuels. The shredding or mixing apparatus usually comprises a tank or so-called xe2x80x9chousingxe2x80x9d which received the bulk material and which, in the preferred embodiment of the invention, is a bulk feed material. An auger is located in the tank and is usually mounted in a vertically oriented position. The upper end of the tank or housing is open for the introduction of the bulk material therein.
In accordance with the invention, the auger of the shredding or mixing member may be rotated at approximately the same speed of rotation, or otherwise, the same power level can be maintained by using different speed levels from the power plant which drives the auger. More importantly, manual intervention is provided, such that an operator of the apparatus may manually shift between the various gear ratios without ever, even momentarily, interrupting the power supplied to the auger. In this way, the auger will constantly rotate during any shifting operation.
Also in accordance with the invention, the mixing or shredding apparatus may be fitted with a draw bar, a coupling and a forwardly projecting drive shaft so that the apparatus is suitable for coupling to conventional farm tractors in such a way that the apparatus can travel behind the farm tractor while the latter is being driven. As also indicated, the apparatus may be self-propelling when provided with its own power plant.
The transmission which is used for accomplishing the unique result described herein can be actually fabricated from an existing automatic transmission which is modified to provide the manual assist transmission of the present invention. In this particular case, the transmission is provided with an input shaft and receives input power from the crankshaft output of the engine. In addition, there is an output shaft on the transmission for delivery of power to a rotatable member, such as the auger, at the mixer or shredder.
A power correcting means is located in the transmission for receiving the input power from the input shaft and for converting that power to the output shaft in order to maintain an relatively constant desired output power to speed ratio on the power shaft regardless of the external load imposed on the power source. Further, a shift means which is manually actuable by an operator is capable of increasing or decreasing the power to the rotatable member, such as the auger, without any interruption of power to that auger.
In one embodiment of the invention, the transmission comprises a manually actuable shift means in the form of a lever which can be engaged by an operator and moved to cause a shifting of the transmission to a different power output ratio with respect to the input power. In another embodiment, the shift means may comprise an electrically openable and closable switch as well as solenoids operable in response thereto in order to cause a shifting of the transmission to a different power output ratio with respect to the input power.
The power correcting means allows for increase or decrease in the transmission ratio in order to thereby provide compensation for any increase or decrease of power received at the mixing or shredding apparatus.
In the transmission which is used, the transmission can initially adopt the form of an automatic transmission and which is modified to achieve the power assist transmission of the invention. In these automatic transmissions, shifting between various planetary gear arrangements occurs with oil or other fluid under pressure. Consequently, the transmission is provided with a main oil pump in order to provide the oil or transmission fluid under pressure. The oil pump is designed only to operate in a single direction and which may be, for example, a counter-clockwise direction. However, the auger must be rotated only in one direction and never in the opposite direction, or otherwise it could seriously damage the auger blades as well as the power train to the shredder or mixer. Furthermore, the speed of rotation of the oil pump must be much higher than the speed of rotation delivered to the output shaft of the transmission and, hence, the auger of the mixer or shredder. As a result, there is needed an input shaft rotation to the oil pump which is opposite the output shaft rotation and also rotation at a different speed for the oil pump. A special planetary gear arrangement is provided for operating the oil pump at a different speed than the remaining portions of the transmission and, particularly, the output shaft thereof and also in a direction reverse to the output shaft of the transmission.
As also indicated previously, it is quite important to insure that the auger in the mixing or shredding apparatus does not rotate in an opposite direction, even momentarily. For this purpose, the shredder or mixer is also used without any forward clutch and a piece of blocking steel in the place of the forward clutch to absolutely prohibit any rotation, even momentarily, in a reverse direction. Also in accordance with the present invention, there is torque converter provided in the transmission housing.
In addition to the above, the input shaft of the transmission is mounted so that it can shift in and out in order to isolate directional force changes imposed on the transmission. This is typically due to the fact that when the mixer or shredder on its own chassis is pulled by a tractor, the angular location of the tractor in a turning movement will impose axial shiftable moving forces on the PTO shaft and, hence, on the input shaft to the transmission. The present invention thereby compensates for this problem.
The present invention can thereby be described in one aspect as a transmission for delivering of power from a power source to a mixer in which power from the power source could vary depending on other loads imposed on the power source. This drive train transmission comprises;
a) an input shaft to said transmission;
b) an output shaft on said transmission for delivering power to a rotatable member at said mixer;
c) power correcting means in said transmission receiving input power from the input shaft and connecting power to the output shaft to maintain a relatively constant desired output power on the output shaft regardless of external load imposed on the power source; and
d) shift means manually actuable by an operator to increase or decrease the power to the rotatable member without any interruption of power to the rotatable member.
In another aspect, the present invention can be broadly described as a mixer or shredder apparatus for mixing or shredding a bulk material and for being pulled by a driven vehicle. This apparatus comprises:
a) a chassis with wheels mounted on an underside thereof to enable movement on a ground surface;
b) a draw bar extending from said driven vehicle and being adapted for connection to said chassis;
c) a mixing or shredding tank mounted on said chassis and having rotatable auger therein for mixing or shredding the bulk material;
d) a power source for providing power to the auger;
e) a transmission for enabling a shifting of a gear ratio between the power source and the auger; and
f) means associated with the power input end of said transmission to compensate for any difference in distance between the driven vehicle and the point of connection of the draw bar to the chassis and the angular relationship between the power source or pulling tractor and the chassis.
This invention possesses many other advantages and has other purposes which may be made more clearly apparent from a consideration of the forms in which it may be embodied. These forms are shown in the drawings forming a part of and accompanying the present specification. They will now be described in detail for purposes of illustrating the general principles of the invention. However, it is to be understood that the following detailed description and the accompanying drawings are not to be taken in a limiting sense.